


The Replacement Engineer

by pherryt



Series: SPN ABO Bingo [16]
Category: Supernatural
Genre: (nothing happened), Doctor!Dean, F/F, F/M, Freefall, Implied Annie "Alex" Jones/Claire Novak, Implied Switching, M/M, Mentions of Other Minor Characters - Freeform, No gravity, SPN ABO Bingo, Sam Is Scarred For Life, Scenting, Sci Fi AU, Sex in Freefall, Top!Cas, True Mates, a/b/o dynamics, bottom!Dean, engineer!Cas, everyone is embarrassed, implied past attempt at non con, omega!cas, omega!dean, space ship
Language: English
Status: Completed
Published: 2017-11-25
Updated: 2017-11-25
Packaged: 2019-02-06 15:09:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,061
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12820191
Author URL: https://archiveofourown.org/users/pherryt/pseuds/pherryt
Summary: Dean's the doctor on Charlies ship, and he's just met Castiel - the replacement for their previous engineer. Nobody expected them to take such an instant liking to each other.After that, it was only a matter of time before Sam was scarred for life and Charlie needed to give the ship a few upgrades.But it wasn't really their fault!





	The Replacement Engineer

**Author's Note:**

> This is the last square for me to write (but not the last one for me to post) to fill my card. it fills the Scenting square on my Bingo Card.
> 
> Note, the name of the ship is a Robert Heinlein reference. Time for the Stars was always one of my faves of his.
> 
> thanks go to 3 different people for this fic. I was looking for a setting/backdrop and Dr-Dean gave me True Mate fluff or Smut and Jdragon suggested something in space. Rw_weaden then took a look over the finished story - not as a beta, but just to see if it worked and then agreed with my idea for the ship name :D thanks for the help - you guys are awesome :D

Doctor Dean Winchester pushed himself off the ‘floor’ and floated up through air, his stomach twisting as soon as he didn’t have anything solid under his feet anymore. The other side loomed close a little too fast, and he frantically grabbed the hand holds on the wall, pulling himself through the ‘door’.

After years of being in space, you’d think he’d have gotten used to the weightlessness that certain areas of the ship possessed, but he hated every minute of it.

Which was why he normally tried to stick to the areas of the ship that _needed_ gravity for the best results. Like surgery. He practically lived in the medbay, and that’s the way he liked it.

But Captain Bradbury had called a meeting and Dean was already 10 minutes late. He was pretty sure Charlie was just going to be introducing their new engineer, but first impressions mattered. Even if Dean was positive nobody could replace Benny. At least he had a good excuse. Kevin had slipped when ‘walking’ between sections and bashed his head on one of the handholds. He’d needed a dozen stitches, and somebody was going to have to go out and catch all the blood.

That somebody was probably going to be him, twisting stomach or not.

He was halfway up to the briefing room when the scent hit him. This time it was Dean who smacked into the wall a little too hard. He snagged a handhold, not even registering the pain in his thigh as he closed his eyes and inhaled.

 _What_ **_was_ ** _that?_

Inhaling again, he followed the trickle of scent, all thought of the meeting forgotten completely. The fact that he was navigating weightless corridors quickly, with no hint of nausea or uneasiness, went unnoticed.

Without realizing it, he was outside the very briefing room he’d originally been heading towards. He floated through the door, still sniffing, heedless of the fact that he wasn’t being very discreet at all.

Dean’s eyes glazed over as the scent washed over him.

“What _is_ that?” he groaned.

“Dean! Dean! Snap out of it!” Charlie's voice broke through and Dean blinked, looking around.

“Huh?” He took in those assembled – Captain Charlie Bradbury of course, his brother Sam – he was the navigator for “The Torchship” while Dorothy Baum was pilot. She sat close to Charlie. It was the worst kept secret that Dorothy’s bunk was _never_ slept in.

And floating at ease in the room, at right angles that would normally have caused Dean to whimper, was the most gorgeous man he’d ever seen. Messy, dark hair, scruffy face, the bluest blue eyes, and some sort of grease dotting his coveralls.

The intoxicating scent Dean had been following belonged to him.

He couldn’t figure out what it was, exactly. Dean had no words for the things he could smell coming off their new engineer but it felt _right_. And if the expression on the still nameless engineers face was anything to by, Dean wasn’t alone in this thinking.

A giggle caught his ear and Dean blushed as he realized how close he’d drifted to the man. The giggles turned into exasperated laughter.

“Dean, meet our new Engineer, Castiel Milton. Castiel, this is Doctor Dean Winchester,” Charlie was grinning broadly.

“Nice to meet you, Doctor,” Castiel said, shifting to right himself to be on Dean’s level. His gravelly voice made Dean whimper and the engineers eyebrows shot up, a small smile quirking at the corners of his mouth.

He held out his hand. Without looking away, mouth dry, Dean took it in his own and shook it. “D-dean, uh, um, just…just call me Dean.”

“All right, Dean. Call me Cas.” Their hands lingered and the room held its breath as the two men held their gazes for several long moments. It didn’t look like they were going to break it up anytime soon, so Sam cleared his throat.

“Hey, uh, Dean? Wanna let Charlie finish the intros before you seduce our engineer?”

Dean turned red and yanked his hand away, the momentum sending him careening into his brother. Sam caught him easily and steadied him while Dean flushed and tried to look everywhere other than Castiel.

With Cas’s eyes burning into Dean’s skull, he swiftly relented.

The rest of the meeting was quick, but Dean spent all of it staring at Castiel who was simply staring back. When Charlie asked if anyone wanted to volunteer to give Castiel a tour, Dean nearly leaped at the chance, with a breathless, “I’ll do it!”

“Of _course_ you will,” Sam muttered. Dorothy rolled her eyes as Charlie giggled again. She shooed everyone out, still giggling.

Rolling his eyes, Sam headed off to the bridge, his long form stretched out behind him like a string bean as he floated through the corridor.

“So, um, how long you been an engineer?” Dean winced at the stupid question.

“Born and raised on a ship. Been doing this before I could walk,” Cas answered, that same quirking smile gracing his lips.

Dean felt his heartbeat triple in his chest.

“Oh cool,” he said, pushing off the wall.

“What about you?” Cas asked, following after.

“Station born. Not quite gravity, but wasn’t freefall either. Still can’t get used to it. Then I went dirtside for medical training – god, I never felt so heavy in my _life_. I went dirtside while Sammy – the tall one, he’s my brother -  apprenticed out with Singer. I got back, and Singer took me on, but when he retired, he turned it all over to Charlie. So I been out here about 6 years, while Sam’s been out here longer.” Much as Dean might not like it, with his attention distracted by the handsome engineer – he wondered what the man's designation was, but didn’t want to be rude and ask – he glided effortlessly through the halls, pointing out various things.

Occasionally, they hit the pockets of the ship with gravity and they touched down, looking around the mess, or the gym, or wherever else they’d wound up. Dean was surer on his feet than Castiel in those spaces, but he supposed that had to do with their differences in growing up.

It was still a great effort not to stick his nose in Cas’s neck just to smell that delicious scent.

“So um, why the change of scenery?” Dean couldn’t help but ask.

“I might have punched my previous captain. He wouldn’t erm…respect my boundaries.”

“Wait…what the hell did he do?” Dean blinked as Cas just stared at him stony faced and Dean paled. “No! He didn’t! Holy fuck, Cas! Yeah, I’d say good riddance too.”

“I’m hoping that won’t be an issue on this ship,” Cas conceded.

“Well, you certainly won’t have to punch the captain. Or the pilot. They think we don’t know, but they’re totally into each other. And Sam would _never_ do anything like that,” Dean said emphatically. They passed out of the gravity pocket and back into a weightless corridor and Dean felt his stomach flop. He pushed off the wall, trying to get away from Cas’s scent.

“How about you, Dean?”  Cas asked, following after Dean gracefully. Dean looked backwards for an instant, trying to get a read on Cas’s face, through his scent.

“Gee, Cas, I –“

The engineer’s eyes widened, and he shouted, “Dean! Look – “

Dean collided with the wall, his momentum much greater than it should have been in his rush to escape.

“-out…Oh god, are you okay?”

Cas grabbed a handhold on the side of the wall and did a graceful flip and stop in order to catch Dean on his rebound. Dean held a hand to the back of his head and squeezed his eyes shut.

“Ow…fuck. I’m a fucking moron,” Dean groused.

“Which way’s the med bay?” Cas asked, worry clear to both ears and nose.

Dean squinted his eyes open and pointed. Cas nodded, pulled a rag out of his overalls – a surprisingly clean rag – and wrapped it around Dean’s head. “I know it’s not much, but, I’m not the doctor. That’ll hold till we get you help though.”

Dean nodded at Cas’s words and Cas grasped Dean’s arm and with quick, controlled movements, got them headed in the right direction.

It was torture being this close to Cas. The pain in his head could only distract Dean so much from the warmth of the engineer’s body, the firm grip of his fingers, and his neck – where the scent was strongest – was just so close. Dean’s head dropped onto Cas’s shoulder and he inhaled before jerking back upright, the motion causing a sharp pain in his head.

Cas had to compensate for Dean’s motion and he pulled them to a stop even as Dean moaned. He looked at Dean with worried eyes. “What’s wrong?”

“’m sorry, Cas, didn’t mean to…” Dean mumbled. “You smell so good…’m sorry. Not gonna do an’thin’, promise.”

“Oh,” Cas pinked and ducked his head, but pulled Dean back into an embrace. “I’d like to get to know you first, but I’m pretty sure we’re True Mates, Dean. I, um, rather like your scent too. It’s been incredibly difficult not to bury my nose in you.” His next words were quiet, rushed out, his indefinable scent taking on a tinge of embarrassment. “And um, it’s okay with me if you do.”

“Yeah?” Dean worried at his bottom lip, hesitant to drop his head back to Cas’s shoulder. “But what about…yer last ship…you said?”

“Ah! Well, you’re different,” Cas said with another blush, getting them moving again. “I could tell from the start that we were both drawn to each other, but you’ve made an effort to be respectful of me. Your captain speaks highly of you and, unlike my previous posting, the attraction is uh, mutual. If I said no, I get the feeling you’d back off, even if it hurt to do so. But I’m not. Saying no, I mean. So...” They hit a junction and Cas paused. “Which way?”

Dean pointed, his eyes drifting shut as the comforting scent of Cas somehow soothed the ache in his skull. It was a better sedative than any he’d ever had to use before, and he wondered if he could bottle it up. _No, stupid. That wouldn’t work for anyone but me_.

Before Dean knew it, they’d made it to the med bay. Kevin was long gone, but his assistant, Claire was there. She took one look at Dean being supported by Cas and rolled her eyes.

“What’d you do this time, old man?”

“Hey! I’m not old!” Dean protested, then winced.

“He hit his head. There was blood.” Cas, walking carefully in the gravity, guided Dean over to a med table.

Claire sighed. “Yeah, I see that. What idiot thing were you doing, boss?”

“Shut up and just give me the stitches okay?” Dean grumbled. Cas pulled away as Dean settled on the med table and he whined, then looked away in embarrassment.

Claire blinked between the two of them and shook her head with a chortle. She set to work without a word, cleaning and stitching the wound. It didn’t take long before she was done. She smacked Dean on his shoulder.

“Okay, old man, off to bed with you. And you! No hanky-panky while Dean’s on the good stuff.” She outright laughed at his offended look.

“What about concussions?” Cas asked. “Shouldn’t he stay awake?”

“Nah, I’m good Cas. She gave me the same cocktail I gave Kevin earlier. As much as Claire’s a pain in my ass, she’s not so bad at this,” Dean explained.

She snorted. “Your words of praise are going straight to my head, Dean. Now, you take your boyfriend and get outta here.”

Dean turned red and ducked his head and Cas took his hand. “It’s okay, I told you I’d like to get to know you. That’s what boyfriends are for, right?” Suddenly nervous, Cas blurted, “Are _you_ okay with this?”

Looking up at Cas shyly, Dean smiled. “Yeah, Cas...more than okay.”

“Oh my god, you two are gross. I need nose plugs right now. Get out of here before I go into a saccharine coma,” Claire grumbled, putting away her kit.

Blushing – _again, goddammit! When had he turned into a fucking tomato_? – Dean quickly left the med bay, Cas on his heels as they made their escape. In no time, Dean found his bunk, discovering that Cas’s was close by. There was a very, very faint gravity here, and the two of them were soon side by side on Dean’s bunk, hands held, knees touching, talking quietly.

Even without Claire spreading the news, it didn’t take long for the entire ship to know there was something up with Dean and Cas. Nor did it take very long for them all to agree with her opinion on how sickeningly sweet they were together. All soft smiles and lingering touches.

Everyone took bets on when the first kiss would happen.

Within a month, it changed from mild amusement to the rest of the crew going to Charlie to beg that the engineer and the doctor be given their own room together, just so the crew would stop walking in on them doing _anything_.

“My eyes are gonna burn right out of my skull! I don’t need to see my brother like that!” Sam complained

“God, Sammy, it was _one time_! You act like you keep running into us wherever we go!” Dean groaned, hiding his face while Cas rubbed his shoulders, his nose buried in Dean’s hair, effectively hiding how red he’d turned as well.

**Bonus Scene**

“Are you sure nobody ever comes here?” Cas asked as Dean kissed his neck, sliding the coveralls off the engineer. Cas toed off his boots even before Dean gave an answer, the footwear floating away. Cas’s fingers were fumbling at Dean’s belt and Dean groaned, the vibration over Cas’s neck was amazing.

“Positive, Cas. ‘sides, man, where’re we ever gonna get privacy on this rig? You want me an’ I want you, an’ it’s killin’ me to have to wait.” Dean shuddered as the scent of Cas’s slick hit the air. He whined as Cas pushed away, his naked body graceful as it floated towards a wall, grabbing a couple of handholds to keep himself steady.

“You're right, Dean. I can’t wait much longer either,” Cas panted, “Please? I can smell how wet you are…I need you, need to be inside of you.”

“Oh, god,” Dean groaned. “I need that too. And then afterwards – ?” he trailed off hopefully.

“Then it’s your turn. I can’t wait, Dean,” Cas said with breathless anticipation.

Dean divested himself of his clothes in a rush, the clothes falling away behind them without a care. Dean grabbed Cas’s ankles and pulled himself in towards the engineer, the twist in his stomach having nothing to do with the weightlessness and all about how beautiful Cas was, how both his and Dean’s slick were mingling, their scent thick in the air.

They were too lost in each other, too drunk on the others scents, to notice anything else, until a shriek could be heard above them. Before he could stop himself, Sam’s body, already in motion, flew through the air right into their supposedly deserted corridor. He grabbed at handholds, windmilled his arms in a desperate attempt to reverse direction and leave, but only succeeded in colliding with the two Omegas desperately fucking each other against the wall.

With a shout of horror, Sam realized he had not only collided with their naked, sweaty bodies, but had flown right through droplets of his brother’s come, and they now stained his clothes.

It was a panic filled moment as their limbs tangled, Cas shouting and stiffening, too close to stop, too close to do anything more than register Sam was suddenly _there_ before he came, all wrapped up in Dean’s tight embrace. Cas whined and Dean groaned, thunking his head into Cas’s chest as the two of them realized that due to Sam’s interruption, they’d not made their mating official as they’d planned.

“Sam. Get the fuck off me,” Dean said flatly, not even bothering to take his head away from Cas’s chest. Cas soothed a hand up and down Dean’s naked back. He, too, refused to look at Sam.

“Dude, I’m _trying_ ! You think I wanted in on _this?”_ Sam’s voice was horror filled.

“Man, what are you even _doing_ down here? We wanted some goddamn privacy for once. We _tried_ – honest to god, Sam, we _tried_ to find a spot where no one would walk in on us. Not everyone gets a cushy bunk like the captain, you know.” Dean said defensively.

Sam muttered and looked away. Having finally stopped flailing his limbs, he’d managed to extricate himself. Dean was about to ask him to repeat that when a voice called down the corridor and Sam turned red.

Cas’s eyes narrowed. “It would appear that Sam was attempting to do the same as us. With Jess, if I’m not mistaking the sound of her voice.”

“Sam? Where are you?” Jess’s voice floated toward them uncertainly, getting a little closer every second. Sam’s eyes widened and he was galvanized into motion.

“No, Jess! Don’t come in here!” he pushed off the wall, almost kicking Cas in the head as he did so, but he was too late to stop Jess’s head from popping through the opening.

Her eyes went wide as she took in the scene, Dean’s bare ass on display, Cas still inside him, both of them completely naked and all three men bright red, Sam beelining for her.

She started laughing.

And didn’t stop until it was time to make dinner for the ship. And even then, she couldn’t stop chortling and shaking her head as she recounted the story of the misadventure to the rest of the crew. Both Winchesters and Cas wanted to die of embarrassment on the spot, and Sam insisted he’d been scarred for life.

Charlie wasted no time in repurposing a couple of lesser used areas of the ship into private rooms, for which the rest of the crew were damn thankful.

It was about time, Claire thought, as she stared thoughtfully at Alex, Jess’s co-cook, a slow smirk spreading over her cheeks.

 


End file.
